1 Pulmonary Section, Denver VA Medical Center, Denver, CO 80223, USA; Center for Genes, Health and Environment, National Jewish Health, Denver, CO, USA; Department of Epidemiology, Colorado School of Public Health, Aurora, CO, USA. Electronic address: nicholas.walter@ucdenver.edu.
2 Department of Epidemiology, Colorado School of Public Health, Aurora, CO, USA; Denver Public Health, Denver, CO, USA.
3 Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA; Pulmonary, Critical Care, and Sleep Medicine Section, Yale School of Medicine, New Haven, CT, USA.